They should have done it for the beginning of last season when the new car was released. Now everything will have to wait until the 4th gen which would be in 2016 when it all combines. DP teams won't want to pay for extra stuff now, even if it is for safety reasons.
It was a horrible accident but I don't think the impact was that unusual compared to other crashes where drivers have escaped with much less serious injuries. I expect the actual speed differential will be lower than whatever the speculation is on the internet, which seems to be suggesting around 100mph. The Ferrari wasn't stationary at the point of impact and is another car that is slightly heavier than the DP, not an immovable object.
I'd rather be in an open top LMP car (or 20 year old open top IMSA car) with some form of front impact attenuator. The Ferrari probably wouldn't come anywhere near the driver's cell if there had been some kind of decent crash structure a in front of the driver's legs...
This is just ridiculous for a car class that only started 10 years ago, the front end protection looks like it came straight out the 70s. Crash structures can be simple metal tubes, of which sufficient test data and empirical models are available to even avoid the need for crash testing. You will find a far better example of a front end crash structure on a modern road car.
It has completely failed, just look at where he has ended up, his head is above the original roofline. Looking at the picture of the Fabcar DP it would seem they have less structure to stop the chassis buckling than is commonly fitted in the form of door bars to production car rollcages.